Injection head for excitation of fluid

Abstract

The invention provides a head for a fluid excitation device in which a transducer comprising a vibration generation portion and a fluid excitation portion is secured to a flexible substrate using an adhesive layer located between the vibration generation portion and the flexible substrate. An external force-applying structure is not needed to secure the vibration generation portion to the fluid excitation portion, removing a cause of significant vibration damping. Rather than damping the vibrations generated by the transducer, the flexible substrate instead itself moves in co-operation with the transducer, reducing damping effects. The design and manufacture of this arrangement is relatively simple and no complex tuning is required to ensure efficient operation over the entire operational life of the head. The head can be used in a fluid excitation device such as an atomiser or ultrasonic bath.

What is claimed is: 
     
         1 .- 3 . (canceled) 
     
     
         4 . A head for a fluid excitation device, the head comprising a transducer and a flexible substrate, wherein:
 the transducer comprises a vibration generation portion and a fluid excitation portion in the form of a sheet that is secured to the vibration generation portion in a manner that enables vibrations to be transmitted from the vibration generation portion to the fluid excitation portion; and   the transducer is secured to the flexible substrate via a first adhesive layer that is positioned between the substrate and the vibration generation portion;   the flexible substrate has a thickness in the range of 1 to 500 microns; and   the vibration generation portion comprises an upper vibration generation portion and a lower vibration generation portion, and wherein the fluid excitation portion is sandwiched between the upper vibration generation portion and the lower vibration generation portion thereby securing the fluid excitation portion to the vibration generation portion.   
     
     
         5 . The head of  claim 4 , wherein the flexible substrate is a printed circuit board. 
     
     
         6 . The head of  claim 4 , wherein the vibration generation portion comprise a piezoelectric material and the fluid excitation portion comprises a ceramic sheet or a metal sheet. 
     
     
         7 . The head of  claim 4 , wherein the vibration generation portion is ring-shaped and wherein the fluid excitation portion is located within a central hole of the ring. 
     
     
         8 . The head of  claim 4 , further comprising an electrically conductive layer that is positioned between the vibration generation portion and the first adhesive layer. 
     
     
         9 . The head of  claim 4 , wherein the head further comprises first and second electrically conductive layers, wherein the first and second electrically conductive layers are each electrically coupled to the printed circuit board. 
     
     
         10 . The head of  claim 9 , wherein the first electrically conductive layer is positioned between the vibration generation portion and the first adhesive layer, and the second electrically conductive layer is positioned on another surface of the vibration generation portion such that the vibration generation portion is sandwiched between the first and second electrically conductive layers. 
     
     
         11 . A fluid excitation device, comprising the head of  claim 4 , coupled to a fluid reservoir. 
     
     
         12 . The fluid excitation device of  claim 11 , wherein at least one fluid test hole is formed in the flexible substrate to enable testing of fluid in the fluid reservoir. 
     
     
         13 . The fluid excitation device of  claim 11 , wherein the device is an atomisation device. 
     
     
         14 . The fluid excitation device of  claim 13 , wherein the fluid excitation portion includes a plurality of holes and the fluid reservoir is mounted below the head such that vibrations in the fluid excitation portion draw fluid from the fluid reservoir through the plurality of holes to generate droplets at an upper surface of the fluid excitation portion. 
     
     
         15 . The fluid excitation device of  claim 14 , wherein the plurality of holes are formed by a mesh. 
     
     
         16 . The fluid excitation device of  claim 11 , wherein the fluid reservoir is mounted above the head such that vibrations in the fluid excitation portion are capable of exciting corresponding vibrations in a fluid in the fluid reservoir to generate droplets of the fluid. 
     
     
         17 . The fluid excitation device of  claim 11 , wherein the device is an ultrasonic bath, and wherein the fluid reservoir is mounted above the head such that vibrations in the fluid excitation portion are capable of exciting corresponding vibrations in a fluid in the fluid reservoir. 
     
     
         18 . The fluid excitation device of  claim 11 , wherein a fluid-tight seal is formed between the head and the reservoir. 
     
     
         19 . The fluid excitation device of  claim 18 , wherein the fluid-tight seal is formed at least in part by an edge of the fluid reservoir being arranged in sealing contact with the flexible substrate. 
     
     
         20 . The fluid excitation device of  claim 11 , further comprising a flotation device coupled to the head.